Interesting-
The USB-PCI or USB PCIe controller passes back to the host the data. The bandwidth of the controller can be very high (Gbps) but the USB side is specific. A USB 2 controller will share the 480 Mbps among its connections. 2 drives on one controller will need to share the 480 Mbps. Same for audio. USB3 can do 5 Gbps and even 10 Gbps over PCIe. Its not the host bus that is an issue.
My late model Intel I7/X77 motherboard only has 3 USB controllers. 2 USB 1/2 and 1 USB3 controller. It seems they also can have virtual controllers.
I have never seen a motherboard with 7 internal USB controllers. They would need to be external since the chipset would not have that many. it must have a real forest of USB connectors on the back and front of the box.
Windows does not have native support for UAC 2, needed to handle 176 and 192 sample rates. There are several aftermarket drivers that can provide UAC 2 for Windows. Some 192 USB cards use a different way to pass audio, bulk transfer, which can easily cause problems when some higher priority traffic bumps the audio. UAC2 audio prioritizes the audio as isochronous with reserved bandwidth for the audio stream. However the CPU could still miss an interrupt and drop audio if its loaded and the priorities aren't managed well. There are some tools for testing this. Its an issue in DAW's and usually requires major efforts to remove unnecessary background stuff.
If you really want to know more on the audio interfaces there are computer audio sites with lots of info and about as much SNR on good data as here.
4 are native to the MB chipset , the other 3 are a 3rd party chip on the PCI-E
bus. (but that chip is on the MB , too) ... not a card .
Those first 4 are terminated on the MB itself (8 ports) ,the USB 3 ones are headers. I have one of those headers connected to a front usb 2 port ..
it works as usb 2 without the drivers.
Those "enhanced " ones are the usb 3's , I installed the drivers ... device manager changed. I suppose AMD is more "USB centric' than intel . My older
2 core duo intels had just basic 2 hub USB on the southbridge
.If I connected all my headers ... yes - I would have a "forest" (of wires , too).
OS
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Jack Bybee is a different case: I have been 'surprised' by what he can demonstrate in changing audio quality. I don't consider him as brilliant as Richard Heyser or Michael Gerzon, but apparently he was quite a physicist decades before I met him. I did come to realize that I knew relatively little about the true state of atoms and electrons, as well as the flow of electricity. I tried fairly hard to catch up and at least have a definitive answer to how electricity flows in a wire (for example) but it still remains a relative mystery to me, even with a bookshelf of books on the subject. Jack is still a good friend of mine, and has a very good audio system, one of the best I have ever heard, but not the only audio system that is that good. I know two others in the Berkeley area who have Bybee components in their systems and sound even better.
We are referring to the Adum4160 isolator though that can only do 12Mbps so the controllers in the PC become a moot point.
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Internal Jitter 300ps RMS, no good for audio work?
I don't know. Expect spec to be conservative. But, it is good enough to begin with..... will go better/lower as the testing results warrant.
-RNM
Does this seem like a reasonable quality DAC for the price?
Free Shipping PCM1794+WM8805 DAC decode board Decoder (not including USB card)-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
And if not, can someone suggest a cheap 24-bit 192KHz DAC that is?
Free Shipping PCM1794+WM8805 DAC decode board Decoder (not including USB card)-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
And if not, can someone suggest a cheap 24-bit 192KHz DAC that is?
The problem is that cheap usually also means nasty - not necessarily so, but typically.
Internal Jitter 300ps RMS, no good for audio work?
The real question is, what are you going to measure? I would think of measuring the jitter in say a 1kHz tone, and comparing that to the output of the DA process.
The measurements I have done were with a controlled amount of jitter inserted in the stream and checking the impact on audio.
Can this unit also insert controlled jitter amounts?
BTW In my tests I did not see any issue with the analog output until I increased jitter to 50nS pk-pk or so...
Jan
To many PTH decouplers for my taste
but at the price I may even get one myself for or I may look at this found on same page:YJ daul AC12V 0 12V NE5534 + AK4399 + SA9227 DAC USB decoder board suppoert PCM model-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
Incredible prices, great for doing a little stand alone system
Any recommendation?
We started with AduM4160 and it’s limitations but IMHO it’s good to know what happens within the PC, especially so when many of USB BW limit exceedance cases (dependent on devices connected, mode of communication and which one was connected first) can lead to intermittent data transfer problems, maybe unnoticed at the time they occur but certainly mind puzzling.
(besides, not everyone has an updated PC motherboardand.)
I always appreciate the contribution of participants who know what they are talking about
George
To many PTH decouplers for my taste
YJ daul AC12V 0 12V NE5534 + AK4399 + SA9227 DAC USB decoder board suppoert PCM model-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
Incredible prices, great for doing a little stand alone system
Thanks, I can't find a datasheet on the SA9227 though. It seems it may be like the PCM510x, compromised THD+N and dynamic range in order to achieve 384KHz samplerate, which is not my target (though I would like to experiment with it).
More on jitter, from what I have gleamed from posted notes and internet searches the audibility from listen tests does seem to be around 10ns (in some very rare cases less than that).
The Well-Tempered Computer
The Well-Tempered Computer
Is that the film score recordings? Been trying to get those for a while but scary pricey. Lots of cheaper versions that are not conducted by Morricone.
For just over £30 UK I wont grumble, my lad wants a better set up in his bedroom so space is at a premium and he starts college in a few weeks so it can be a nice project for him (plus he's buying some of the parts out of his upcoming 16th birthday money) BONUS for me. I am donating some speakers I found in a box from my FR days (Fostex 166 and Eminence 12")and the cabinets. We did have some little amps both chip amp based and some with built in heatsinks that I had rescued from some test gear, but they seem to have disappeared, so cheap amps and crossover next.
Even more on jitter...
The contention is that very low rate clock centre frequency variance is relatively very high in amplitude (1/f noise characteristic) wrt audio band jitter, and is subjectively much more destructive."Low Rate Uncorrelated or Noise-Like Jitter" - to quote Paul Miller.
So there you are, we even have a "name" for it, albeit a cumbersome one.
This kind of jitter is very hard to measure. But it is also the kind of jitter that makes digital sound DIGITAL. Peculiarly, the other forms of jitter are far more likely to make sonic differences that are perceived as analogue differences. Hence we can hear the differences in digital cables etc., as Harley points out, things like digital cables takes on analogue behaviour.
But rarely are these difference DESTRUCTIVE in nature, more like "voicing" in speakers and we pick our preferences.
But we are targeting something beyond "voicing" - something OBVIOUS to the ear as WRONG, something we have collectively coined... DIGITITUS !!!
UNL Jitter, Uncorrelated Noise-Like Jitter.
The Terra Firma Concept: Jitter is Analogue
This is why I have in the past mentioned jitter spectrum.
White noise clock instability causes a, well, white noise noise cloud over the reproduced audio.
VLF clock instability causes a 'vibrato' effect, and this is distinctly audible causing general lack of image clarity and stability, in particular centre placement and depth imaging, and sense of wrong pitch.
Allan Variance
AllanVariance/
Science Of Timekeeping
Dan.
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